Alloy for making ductile iron

ABSTRACT

A process for producing ductile iron comprising adding to a bath of low-sulfur cast iron, a material containing at least two graphite-nodularizing elements. The additive material contains each nodularizing element in relatively low concentrations so that after dissolution in the bath the concentration of nodularizing elements remaining is sufficient to produce the desired structure, but the concentration of any one element is, of itself, insufficient to produce nodular (spheroidal) graphite.



1. A NODULARIZING COMPOSITION FOR USE IN THE PRODUCTION OF NODULAR CAST IRON COMPRISING AT LEAST TWO NODULARIZING ELEMENTS IN A SILICON-IRON ALLOY OR MIXTURE OF SILICON-IRON ALLOYS, SAID ELEMENTS SELECTED FROM THE GROUPS CONSISTING OF MAGNESIUM, CERIUM, YTTRIUM, LANTHANUM, NEODYMIUM AND PRASEODYMIUM WITH EACH BEING PRESENT IN THE ALLOY OR ALLOYS IN AN AMOUNT OF FROM ABOUT 1 TO 3 PERCENT BY WEIGHT OF THE COMPOSTION AND THE TOTAL AMOUNT OF NODULARIZING ELEMENTS IN THE COMPOSITION NOT EXCEEDING MORE THAN ABOUT 12 PERCENT.
 2. The composition of claim 1 wherein the nodularizing elements are magnesium and cerium in substantially equal amounts.
 3. A nodularizing composition for use in the production of nodular cast iron comprising at least two silicon-iron alloys, one alloy containing magnesium in an amount of from about 1 to 3 percent by weight and the other alloy comprising at least one nodularizing element selected from the group consisting of cerium, yttrium, lanthanum, neodymium and praseodymium with each being present in an amount of from about 1 to 3 percent by weight of the alloy and the total amount of nodularizing elements in the composition not exceeding more than about 12 percent.
 4. A nodularizing composition for use in the production of nodular cast iron comprising at least two nodularizing elements and one of said at least two nodularizing elements being magnesium and being present in a silicon-iron alloy from about 1 to 3 percent by weight of the composition and the remainder of said at least two nodularizing elements selected from the group consisting of cerium, yttrium, lanthanum, neodymium and praseodymium, each being present in about the same amount as said magnesium and the total amount of nodularizing elements in the composition not exceeding more than about 12 percent. 